RNA Polymerase: Interaction of RNA and Rifampicin with the Subassembly α2β

Abstract
The inhibition of tryptic digestion of the subassembly .alpha.2.beta. of Escherichia coli DNA-dependent RNA polymerase was studied to investigate its interaction with RNA and rifampicin. Both agents decreased distinctly the cleavage of subunit .beta. in the subassembly and the degradation of the transiently formed polypeptides (MW > 80,000). Short RNAs with a chain length of approximately 35 nucleotides were most protective at a concentration of 1 mg/ml, while long RNAs were less effective at the same concentration. DNA did not exert any observable protective effects. The association of RNA with .alpha.2.beta. was shown by chromatography on phosphocellulose, which separates .alpha.2.beta. bound to RNA from free .alpha.2.beta.. The association of .alpha.2.beta. with RNA was inhibited by rifampicin.